The present invention relates to a machine in which a moving part is moved by means of a direct drive.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
A direct drive is frequently provided in the form of a so-called built-in motor. The machine manufacturer receives the stator and the armature (stator and rotor) of the machine, the armature not yet being definitively mounted with respect to the stator. Rather, the actual mounting of the armature with respect to the stator takes place within the machine. The stator is connected to a first other component of the machine and the armature to a second other component of the machine, usually rigidly. The second other component of the machine is now mounted relative to the first other component of the machine, thus producing an indirect mounting of the armature with respect to the stator. If an electric motor is used as a direct drive, operation of the motor is dependent on how accurately a pre-determined air gap is maintained between stator and armature, in particular between the active regions of the stator and the armature, in which the acting magnetic fields are provided. The mounting of the machine often proves to be inadequate to adjust the air gap precisely. This problem is compounded, when large machines are involved. If a rotary motor is used in which the rotor must have a diameter of three to five meters, the mounting in a machine of the type described above represents a challenge. If the machine has a diameter of as much as 20 to 50 meters, which can be the case with modern telescopes and also wind turbines, previous mechanical engineering concepts prove to be unsuitable.
It would therefore be desirable and advantageous to provide an improved machine with direct drive to obviate prior art shortcomings.